1. Field
This disclosure relates to a backlight unit and a liquid crystal display device including the same.
2. Description of the Related Art
Liquid crystal display (“LCD”) devices are a type of display device which form an image by receiving external light instead of using self-emitted light to form the image, as is the case in plasma display panels (“PDPs”) and field emission displays (“FEDs”), for example. Thus, the LCD device uses a backlight unit for emitting light at a rear surface of the LCD device.
A backlight unit for an LCD device can use a cold cathode fluorescent lamp (“CCFL”) as a light source. However, when the CCFL is used as a light source, it is difficult to provide desirable uniformity of luminance of light supplied from the CCFL and color purity deteriorates as a screen size of the LCD device increases.
A backlight unit which uses three color LEDs as a light source has been recently developed. Since the backlight unit using the three color LEDs as the light source produces improved color purity, as compared to the backlight unit using the CCFL, it can be used to provide a higher quality display device, for example. However, the backlight unit which uses the three color LEDs as the light source is more costly as compared to the backlight unit which uses the CCFL as the light source. To mitigate this problem, a white LED which emits light by converting light output from a single color LED chip to white light has been proposed.
However, although the white LED is not as expensive as the three color LEDs, color purity and color reproducibility are reduced as compared to the color purity and color reproducibility of an LCD device including the three color LEDs. Accordingly, various attempts for developing semiconductor nanocrystals as light converting materials to improve color purity and color reproducibility while maintaining price competitiveness have been made. Thus there remains a need for an improved backlight unit.